Indexing mechanism



Jan. v14, 1941. v F. A. PARSONS' INDEXING MECHANVISM Filed Jan. 21',1937 2 sheets-Sheet 2 Jan. 14, 1941', F. A. PARSONS I-NDEXING MECHANISMFiled Jan. 21, 1957 A 2 sheets-sheet 2 Patented Jan. 14, 1941 UNITEDSTATES PATENT OFFICE azzassa i INDEXING MECBANISM FredxA. Parsons,Milwaukee, Wis., assignor to Kearney and Trecker Corporation, WestAllis,

Wis., a corporation Application January 21, 1937, Serial No. 121,599

somma. (ciaossi movements, and particularly in an improved form.suitable for angular adjustment or indexing of dividing head spindles.

A further object is to provide indexing means of the type just mentionedin a form for interchangeable or alternative use with less highlyorganized'types of indexing mechanism, as for4 instance those now in useon dividing heads andy similar structures.

A further purpose is to provide an improved indexing device as above, ina form suitable for use in the driving train for rotating a work piecein the operation of the cutting of helical grooves or threads. i

Another object is to provide improved indexing mechanism referred toabove and of a form and arrangement suitable to be used on dividingheads of the type generally known as universal heads,- while permittingof the swiveling and ,various other adjustments required of such heads-and permitting` the spindle of the head to be power driven.

. A furtherv` purpose. is to provide improved indexing means useableboth for relatively largev spacings or division and for relatively verysmall spacin'gs and of improved and substantially equal accuracy ineither instance, and conveniently operable for effecting `bothrelatively iineand relatively large spacings in the same series ofspacngs.

A further object is generally to simplify and improve the' constructionand. operation of indexing mechanism, particularly for machine tooldividing heads. and still other objects will be apparent from thisspecification.

The invention consists in the construction, relationship and combinationof parts as herein illustrated, described and claimed, and in lsuchmodification thereof as may be equivalent to the structure claimed.

The same reference characters have been used for the same partsthroughout, and in the draw- Figure 1 is an end view, partly in section,of a universal dividing head incorporating the invention.

Figure 2 is a partial front elevation of the same head viewed from theleft of Fig. 1.

Figure 3 shows a portion of the mechanism as viewed in Fig. 2, partly invertical section approximately along-the line 3-3 of Fig. 1.

Figure4 is a partial `vertical section approximately along .the line 4-4of Fig. 3.

Figure 5 shows a reduced scale portion of the same dividing head, butwith another form of indexing mechanism which is interchangeably oralternatively usable. l The dividing head as here shown includes a basei0 adapted to be iixed on a milling machine orl other machine tooltable, as for instance by l the means of bolts such as I I and a tongueor key Ila. The swivel block I2 is rotatably supported by frame III, androtatably supports a spindle I3. In the position shown in Fig. 1 thespindle I3 is axially parallel to the lower surface of the basev III andvto the surface of the table upon which the head is supported. Themounting of the i Fixed t0 the base In 1s a bracket I4, 1n which isrotatably' mounted a power shaft I5, having suitable coupling means, notshown, for connecting the shaft for power actuation. Carried on shaft I5is a worm I6, engaging a worm wheel I1 l rotatably mounted on a sleeveI8 having an end portion I9 fixed with the swivel block I2 to supportthe worm wheel Il co-axially with the axis of swivel adjustment of theblock. Also co-axial with the block axis, and journaled in .the sleeveI8, is an index shaft 2li having fixed thereon a bevel pinion 2|permanently meshed with a bevel gear 22 which is fixed on spindle' I 3.

The bushing I8 and shaft 20 respectively provide portions IBa and 20aextended to the left in Fig. 1 for supporting and locating indexingmechanism for spaced angular adjustment of spindle Il, the worm wheel I1providing screws such as 23 for attaching an index plate thereto, andthe shaft 2l providing a threaded end 2|Ib and a nut 24 for retainingportions of the indexing mechanism.l

y'.i'he structure thus far described is fully described in thekco-pending application resulting in f Patent No. 2,205,361, issued June18, 1940, and therefore will not be further described. As there shownthe indexing mechanism includes an index plate 25, Fig. 5, fixed withthe worm I1 by screws 5 23 and providing a number of index circles ofvarious' diameter and respectively providing a different number ofequally spaced index holes such as 25a.\ Fixed on the end 20a of shaft20 is an index crank 25 carrying a spring pressed index plunger 21having an end 28 adapted to be alternatively engaged in various of theholes 25a, the plunger being carried in a slotted portion of the l crank25, for adjustment to permit of the cooperation of the plunger withthevario index circles of different diameter. The index plate 25 may berigidly fixed with the base i0 by the means of a clamp ring 29, anchoredwith the base, the clamp ring 29 being provided with clamp means, laterdescribed. The ring 29 may be released to permit the index plate torotate when power is to be applied to drive the worm wheel I1.

In the presentstructure a portion of the ini dexing mechanism justdescribed is replaced by 'other indexing mechanism,` as follows: Anindex plate 3|, Fig. 1 replaces plate 25 and is similarly fixed to theworm wheel I1 by screws l23, and may be fixed or released vrelative tobase I0 by the means of the clamp ring 29 engaging the periphery of theplate, whereby to be rotatable with the worm wheel I1 when power isapplied to shaft I5, or to be fixed against rotation, similarly to theplate of the co-pending application previously mentioned, the clamp ring29 being prevented from rotation by lugs such as 33, 34, Fig.4 2 andclamped or released by a screw such as 35.

Index plate 3| provides index holes arranged inv a circle co-axial withthe shaft 20, the holes being selectively engageable by an index plunger35, urged in engaging direction by a spring 31, but manuallydisengageable by the means of a hand grip member 38. The plunger 35 maybe retained in disengaged position by turning the member 38 slightlyafter disengagement, when a pin 39Will abut the end of member 40 whichcarries the plunger.

The plunger 35. is mounted for rotation on shaft 20, being carried byahousing member 4I having a bearing at 42 on the sleeve I8 and anotherbearing at 43 on a bushing 44, the bushing 44 in turn having a bearingon the hub 45 of a worm wheel 45, which is keyed with the projecting end20a of shaftlll.

'I'he housing 4I is normally prevented from rotation relative to theshaft 20 by the engagement of a worm 48 with the teeth of the worm wheel45, the worm 48 being fixed on a shaft 49 which is rotatably mounted inthe housing 4I, as shown in Fig. 3, but is prevented from axial 60movementl by thrust bearings such as 58, 5I.

The threads of the worm 48 are closely fitted to the teeth of worm gear45, it being contemplated that the worm and Worm wheel may be relativelyadjustable to insure the close fit of the teeth, as for instance byconstructing theworm in the manner shown and described in the Patent No.2,002,644, issued May 28, 1935. By reasonof the construction shown thehousing 4I, worm shaft 49, worm 48 and worm wheel 45 together provide acrank whereby the movement of the plunger 35 from one to another of theindex holes 8Ia indexes the shaft 20 in accordance with the angularmovement of the index plunger. Supplemental index means are provided,operative through the worm 48 as follows: Fixed on the shaft 49 is aworm wheel 52, engaged by a worm 53 flxed on a' shaft 54 journaled'inthe housing member 4I, but prevented from axial movement. `Shaft 54carries a gear 55 engaged by a gear 55 fixed on the sleeve 44 andco-axial with the shaft 20. Fixed for rotation with the gear 55 is anexposed member 51 provided with a hand grip portion 58. The worm wheel52 and worm 53, similarly to the other worm and wheel, may be relativelyadjustable in the manner shown in the Patent 2,002,644, or in othersuitable manner. By reason of this construction described the shaft 20may be indexed independently of movement of plunger 35 through the trainconsisting of the member 51, gear 55, gear 55, shaft 54, worm 53, wormwheel 52, shaft 49, worm 48, and worm wheel 45.

By reason of the structure described, the shaft 20 may be indexed bydisengaging the plunger 35 from the index holes 3Ia, and rotating theplunger, or the shaft 25 may be indexed by rotation of the manual member58 through the train previously described, and in eitherevent the oneindex movement supplements the other, either l adding or subtracting theindex movements according to the relative direction of movement of theprimary manually operated members. The thread angle of the worm 48 issuch that the worm is self=locking, and has no tendency to turn itsshaft or the parts connected therewith when indexing. is effected fromplunger 35. 'I'he plunger locks the other mechanism when thesupplemental index mechanism is in use.

In the construction shown in the drawings th'e gears 2| and 22connecting the index shaft 20 to the spindle I3 are of a five to oneratio, and the index plate 3| has seventy-two equally spaced holes 3 Ia.Therefore the movement of the plunger 35 from the one hole 3Ia to anadjacent hole moves the spindle I3 through an angle of one degree.

Also in the construction shown in the drawings the worm 48 is a singlethread worm. and worm wheel 48 has seventy-two teeth. Therefore movementof the manual member 58 sum- -ciently to turn the shaft 49 through onecomtial rotations of the shaft 49,` and each division of the dial 5|represents one minute of angular index movement of the spindle I3. Thedial 59 may be clamped in various positions of rotation relative toshaft 49 by themeans of a lock screw 53, whereby to move the dial to azero starting point between consecutive index movements.

The gear train consisting-of gears 55, 55 and the worm and wheel 52, 53,as here shown, are of a ratio which move the shaft 49 throughonesixtieth of a revolution for each rotation of the gear 55 and manualmember 58. 'Fixed on the member 51, to rotate with the gear 55 is a dialmember 54, readable against an indicator member 55 fixed on the housing4I.. Dial 54 has sixty equally spaced graduations as indicated in Fig.2. A movement of the manual member 58 sufllcient to move dial 54 onegraduation space relative to the indicator, results in an index movementof the spindle I3 through an angle of one second.

Relatively adjustable sector elements 55, 51

. indexing proceeds by iirst adjusting the one sector fao lug 66a or 61aagainst the. end of the index plunger, then disengaging the indexplunger from the plate, rotating it to engage the hole adjacent thevother lug and reinserting the plunger, followed by turning the pair ofsectors to again engage the plunger as Aat rst. This method avoids thenecessity of counting `the required number of index holes each time theindex plunger is moved in performing a series of index operations.Similarly for the dial 64 there is provided a pair of rotatable sectors69, 10, which can be locked Atogether by a screw 1|, the sectors havinglugs 69a, 10a which may be relatively adjusted to set oif any desiredspace on the dial.

In the indexing of work pieces ixed to rotate with the spindle i3 withthe index plate and index trains as above described, the angular spacingbetween the index positions is first determined in degrees, minutes,seconds and fractional seconds.

, Since the index plate 3| has only seventy-two holes, if there are morethan seventy-two degrees in the required index spacing the plunger 36will be given one or more complete revolution. If the indexing movementrequires a number of degrees which are not an exact multiple ofseventy-two degrees, then such extra degrees of movement are obtained bypartial revolutions of the plunger 36, and for spacing such partialrevolutions the sector lugs 66a and 61a are spaced to include betweenthem as many of the index holes 3|a as are required for the requirednumber of degrees.

Where an indexing movement of spindle |3 is not inA even degrees, butrequires additional minutes, the added movement is obtained by rotationof the manual member 56. This member will be given as many completerevolutions, as determined by the indicator 65, as there are minutes ofadditional index movement required. In this movement the dial 6|provides a counter or indicator as a check on the number of completerotations of the dial 64. Following each index movement of the manualmember 58, the dial 6| may, if desired, be set back to a zero positionby loosening the screw 63.

If an index movement requires seconds of movement, in addition to theminutes and degrees obtained as just described', then in addition to thecomplete revolutions'of the dial 64, the dial is given an additionalpartial revolution depending on the additional seconds of index movementrequired. The lugs 69a and 10a.' of the pair of sectors 69, 10 arespaced to'include between them a dial space corresponding to the secondsof additional index movement required,4 and following each indexmovement the sectors are reset against the indicator in a position toindicate the next partial revolution of the dial 64.

Fractional seconds may be readily set off between the lugs 69a and 10aon the dial 64, but since the space corresponding to one second of arcis entirely negligible in ordinary-instances upon any practical workdiameter, the only reason, ordinarily, for considering fractionalseconds of arc is to provide such surplus of movement as will prevent anaccumulation of errors during a series of index movements.

It is obvious that the device may also be constructed with index circlesand trains which permit the index movement to be computed directly indecimals. Thus, for instance, if the index plate 3| is provided withtwenty holes, then each movement of the plunger 36 from one hole toanother will result in one hundredth of a revolution of the spindle I3.Further if the worm wheel 46 is 4provided with one hundred teeth, andthe gear train from the dial 64 to the shaft 49 provides forone-hundredth revolution of shaft 49 at each revolution of the dial 64,and in addition both the dial 6| and the dial 64 are provided with onehundred graduations, then instead of the degrees, minutes and seconds,the index movement of the spindle i3 vmay be computed in hundredths of arevolution, obtainable by movement of plunger 36, in ten-thousandths,obtainable by complete revolutions of the dial 64 as indicated on dial6|, and in millionths, obtainable by revolution of the dial 64 from oneto another of the graduations, partial millionths of index movement ofthe spindle I3 being obtained by partial divisions on the dial 64.

It will be understood that in ,order to avoid a large number ofrevolutions of the dial 64, it may be desirable in certain instances toindex the plunger 36 through a distance somewhat in excelss of the indexmovement required of the spindle |3, then using the dial 64 to turn the.spindle |3 in the opposite direction in the amount of such excess, thesector pairs being set accordingly.

'I'he supplemental index mechanism, in the construction shown, avoidsspaced index holes principally in order to permit of splitting up thesmallest indicated movement to avoid accumulation of errors, aspreviously mentioned. It is obvious-that spaced index holes and aplunger could be used instead of the dial, but such construction wouldlimit the fractional advance of the mechanism to certain fractions,whereas the mechanism shown provides for any increment of advance.

It is to be noted that in the device shown the entire index mechanism,except plate 3|, may be removed as a unit upon yremoving nut -24, theAgear 46 being removably fitted on shaft end 20a andthe parts carried bysleeve end |8a being also removably fitted. The indexplate 3| and clampring 29 may then also be removed after removing screws 23. Thisconstruction permits the mechanism to be interchangeably replaceablewith that shown in Fig. 5, or with other similar mechanism, such as themechanism, previously mentioned, constructed for indexing spindle |3 inhundredths, thousandths and millionths of a revolution.

Itis further to be noted that the connection of the supplemental indexmechanism through the self-locking Worm and wheel structure and themanner of positioning this structure in the main index train removes allcutting load from the supplemental index mechanism, and also removes allload from the supplemental index mechanism during power rotation of themain spindle. By the construction shown the main index connection can bemade relatively rigid and sturdy to adequately resist the cutting and'an indexable member, a rotatable index shaft, l5

`an index plate providing a series of equally spaced index holesarranged in a circle concentric with the axis of said shaft, a crankmember rotatable co-axially with said shaft, an' index plunger bodilyrotatable with said member for selective engagement with different ofsaid index holes,

l an index train connecting said crank member for rotation of saidshaft, said -train comprisingl supplemental index elements relativelyrotatable to alter the position of said index shaft relative kto thecrank member, manual means for relative tion, the connection of saidother index measuring elements being of such ratio that wholerevolutions of the relative rotation of the first mentioned indexmeasuring elements moves said other index measuring elements onlythrough one of said increments.

2. In an index head the combination of a base providing means forremovable attachment to a machine tool platen, an indexable spindlerotatably carried by said base, an index shaft carried by said base forrotation on an axis transverse to the spindle axis, a connection betweensaid shaft and spindle including gearing, an index plate carried by saidbase and providing a series of equally spaced index holes in a circleco-axial with said shaft, said spindle and connecting gear being axiallyspaced at one side of said plate, said plate providing a bore and saidshaft providing an end portion projecting through said bore at the otheraxial side of said plate; and 'a unitary device removably associatedwith said projecting shaft end at said other side of said plateincluding a crank member rotatable co-axial with saidv shaft, a plungercarried by said crank for bodily rotation therewith to positions forengaging different of said index holes, an index train connecting saidcrank member and shaft, supplemental index means including a pluralityof supplemental index elementsv one of which is rotatable relative tothe other independently of rotation of said crank, an index trainconnecting said rotatable supplemental index element and said shaft, andmeans associated with said supplemental index elements for determiningthe index movement communicated to said shaft upon rotation of saidrotatable element, said index trains being of materially diierent ratio,and means associated with said shaft end for xing said device removablyin operative association in said index head at said other side of saidindex plate.

3. AIn a dividing head the combination of a base providing means forremovable attachment to a machine tool platen, a block swivelablytrunnioned on said' base, an indexable spindle journaled in said Ablockfor rotation on an axis transverse to the swivel axis of said block, anindex shaft co-axial with the swivel axis of said block, a connectionbetween said shaft and spindle including gearing, a gear co-axial withsaid shaft and providing a hub portion, an index plate fixed onsaid hubportion and providing a series of equally spaced index holes in a circleco-axial with said shaft, clamp means operable lfor alternative rotationof said index plate or for fixing the plate in non-rotatable relation tosaid base, said plate providing av bore and said shaft providing an endportion extending through said bore, a crank member rotatable co-axiallywith said shaft, a plunger carried by said crank member for rotationtherewith to positions for engaging different of said inde); holes,anindex train connecting said crank member for rotation with said shaft;and supplemental index means including relatively rotatable indexmeasuring members one of which is rotatable co-axially with said shaft,and a supplemental index train connecting the rotatable member forrotation of said shaft independently' oi' rotation, of said crankmember, said index train and supplemental index train being ofmaterially different motion transmitting ratio.

FRED A. PARSONS.

